[Qemu-devel] [PATCH QEMU] Patches for new AMD CPU bits.

From:

Konrad Rzeszutek Wilk

Subject:

[Qemu-devel] [PATCH QEMU] Patches for new AMD CPU bits.

Date:

Fri, 1 Jun 2018 11:38:07 -0400

Hi!
I was reading the AMD whitepaper on SSBD and noticed that they have added
two new bits in the 8000_0008 CPUID. EBX:
1) Bit[26] - similar to Intel's SSB_NO not needed anymore.
2) Bit[24] - use SPEC_CTRL MSR (0x48) instead of VIRT SPEC_CTRL MSR
(0xC001_011f).
See 124441_AMD64_SpeculativeStoreBypassDisable_Whitepaper_final.pdf
A copy of this document is available at
https://bugzilla.kernel.org/show_bug.cgi?id=199889
These two patches along with the kernel ones allow us to expose those
two bits to the guest.
Thank you!
target/i386/cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Konrad Rzeszutek Wilk (2):
i386: define the AMD 'amd-ssbd' CPUID feature bit
i386: Define AMD's no SSB mitigation needed.